PDB identification codes must be 4 characters long. The first character
must be a digit in the range 1-9. The latter 3 characters can be either
letters or digits. There is no requirement that PDB ID codes contain
a letter, but I do not believe any all-digit PDB ID codes have been
assigned as of year 2000.

Default vs. Expert modes.
PE's preferences must NOT have Expert checked in order for the
non-expert entries below to work.

Expert mode off.
FirstView is described and explained for novices. Next page is "QuickViews".
(1b07)

Expert mode ON. Query parameter is "?x=1&".
The initial page loads the molecule(s), and then
proceeds automatically to the "Advanced Explorer" page.
A two-page sequence is needed because the "Advanced Explorer" page
needs to know whether multiple models are present before it loads.
(This requires that the molecule(s) are already loaded and interrogation
of Chime is completed before proceeding to the "Advanced Explorer" page.)